JP2019195211A - Image forming system - Google Patents

Abstract

To provide an image reading device, an image forming system, and a program that can read the front and back positions of images formed on a sheet accurately at a low cost, and can easily detect sudden displacement of the front and back positions of the images.SOLUTION: Marks A are formed on the front and back of a sheet P, respectively, by an image forming apparatus 5, and an image reading device 7 comprises: a first scanner 701a that reads the mark A; and a second scanner 701b that is provided on the downstream side of the first scanner 701a and reads the mark A. The image reading device includes a position adjustment unit 511 that adjusts the front and back positions of the marks A on the basis of printing positions of the marks A read by at least one of the first scanner 701a and second scanner 701b, and a monitoring unit 513 that monitors displacement of the front and back positions of the marks A on the basis of the front and back positions of the marks A adjusted by the position adjustment unit 511.SELECTED DRAWING: Figure 4

Description

  The present invention relates to an image reading apparatus, an image forming system, and a program.

  2. Description of the Related Art Conventionally, there is an image forming system including a printing machine capable of duplex printing and an image reading apparatus including a scanner that measures and adjusts the front and back positions of an image formed on a sheet using a single scanner (for example, , See Patent Document 1).

  The conventional technique as described in Patent Document 1 conveys a sheet twice in order to read the front and back positions of an image formed on the sheet with one scanner. Therefore, as the image front / back position reading operation is performed for each sheet, the time required for conveyance for reading the image formed on the sheet increases. As a result, the productivity as an image forming system is reduced.

  Therefore, in order to avoid conveying the paper twice for each paper, there are some which read the front and back positions of the image formed on the paper using two scanners. Specifically, an image formed on the front surface of the paper is read by one of the two scanners, and an image formed on the back surface of the paper is read by the other of the two scanners. As a result, it is possible to read the images formed on the front and back sides of the sheet only by conveying the sheet once per sheet.

JP 2006-072075 A

  However, each scanner has a mechanical difference, that is, a machine difference. Therefore, even if two images having the same performance are used to read images formed on the front and back of the paper, the reading positions of the two scanners may be displaced. Therefore, there is a possibility that the front and back positions of the image formed on the paper cannot be accurately read.

  Further, when mechanically adjusting the machine difference of the scanner, high accuracy is required for the component accuracy and the position accuracy, so that the cost for adjusting the machine difference of the scanner increases.

  By the way, as double-sided printing is performed by the printing machine, the front and back position shift may occur in the images formed on both sides of the paper, even though the setting on the printing machine side is not changed. Such front / back position deviation of the image is caused by environmental conditions such as temperature and humidity of the printing place or deterioration of mechanical durability. Therefore, there is a possibility that the front / back position shift of the image due to the environmental condition may occur suddenly.

  The present invention has been made in order to solve the conventional problems, and an object of the present invention is to suddenly read out the front and back positions of an image formed on a sheet while accurately reading the front and back positions of the image at low cost. An object of the present invention is to provide an image reading apparatus, an image forming system, and a program capable of easily detecting a shift.

  To achieve the above object, an image reading apparatus according to the present invention includes a first scanner that reads an image formed on a sheet, a downstream side of the first scanner, and a conveyance path that passes the sheet. An image reading apparatus provided on the opposite side of the first scanner and configured to read an image formed on a sheet, and formed on a first surface of the sheet read by the first scanner Based on the printing position of the mark and the printing position of the mark formed on the first surface of the paper read by the second scanner, or read by the first scanner, the positional relationship based on the same reference from the front and back On the basis of the printing position of the mark formed on the first surface of the original and the printing position of the mark formed on the second surface of the original read by the second scanner, A machine difference adjusting unit for adjusting a machine difference between the first scanner and the second scanner, and when the machine difference is adjusted by the machine difference adjusting unit, a reference position of a mark formed on the first surface of the sheet A position adjusting unit that determines a first reference position and a second reference position that is a reference position of a mark formed on the second surface of the paper; and the first reference position determined by the position adjusting unit; The second reference determined by the position adjustment unit is monitored by monitoring a first reference shift amount, which is a shift amount from a printing position of a mark formed on the first surface of the sheet read by the first scanner. A monitoring unit that monitors a second reference deviation amount that is a deviation amount between a position and a printing position of a mark formed on the second surface of the sheet read by the second scanner.

  According to this image reading apparatus, it is possible to easily detect a sudden front / back position shift of an image while accurately reading the front / back position of an image formed on a sheet at low cost.

  Further, in the image reading apparatus according to the present invention, the first scanner and the first scanner are based on the print position of the mark read by the first scanner and the print position of the mark read by the second scanner. 2 further comprising a machine difference adjusting unit for adjusting a machine difference with the scanner, wherein the position adjusting unit monitors the front / back position deviation of the mark by the monitoring unit when the machine difference is adjusted by the machine difference adjusting unit. It is preferable that an adjustment reference position of the mark serving as a reference is determined.

  According to this image reading apparatus, it is possible to shorten the time required to detect the front / back position deviation of the mark as compared with the case where the image is conveyed twice by one scanner.

  In the image reading apparatus according to the present invention, it is preferable that the machine difference adjustment unit adjusts the machine difference based on the mark formed on the same surface of the paper.

  According to this image reading apparatus, it is possible to accurately detect machine differences between the scanners.

  In the image reading apparatus according to the present invention, the monitoring unit monitors the mark reference position determined by the position adjustment unit when monitoring the front / back position deviation of the mark formed on the sheet. First adjustment reference deviation between the first adjustment reference position of the mark formed on the first surface of the paper and the print position of the mark formed on the first surface of the paper read by the first scanner The amount is monitored, and the second adjustment reference position of the mark formed on the second surface of the sheet among the adjustment reference positions of the mark determined by the position adjustment unit, and read by the second scanner. A second adjustment reference deviation amount with respect to a printing position of the mark formed on the second surface of the paper, and the position adjustment unit includes the first adjustment reference deviation amount monitored by the monitoring unit; Before being monitored by the monitoring unit Based on a second adjusted reference shift amount, adjusts the front and rear positions of the indicia, it is preferable.

  According to this image reading apparatus, it is possible to monitor the front / back position deviation of the mark at a low cost.

  In the image reading apparatus according to the present invention, when the machine difference is adjusted, a master document is used as the paper, and the print position of the mark formed on the first surface of the master document and the master document are adjusted. Each of the printing positions of the mark formed on the second surface is formed at the same position in the front and back penetration direction of the paper, and the machine difference adjustment unit is read by the first scanner. Based on the printing position of the mark formed on the first surface of the master document and the printing position of the mark formed on the second surface of the master document read by the second scanner, the machine difference is determined. The position adjustment unit adjusts the mark formed on the master document as an adjustment reference position of the mark when the machine difference is adjusted using the master document by the machine difference adjustment unit. Setting the print position to the design reference position of the mark, it is preferable.

  According to this image reading apparatus, the machine difference of each scanner and the front and back positions of the mark can be adjusted with high accuracy.

  In the image reading apparatus according to the present invention, the monitoring unit is formed on the first surface of the paper read by the first scanner when monitoring the front / back position deviation of the mark formed on the paper. The first design reference deviation between the print position of the mark and the first design reference position of the mark formed on the first surface of the master document among the design reference positions of the mark set by the position adjusting unit. The master document is monitored among the print position of the mark formed on the second surface of the sheet read by the second scanner and the design reference position of the mark set by the position adjustment unit. A second design reference deviation amount with respect to a second design reference position of the mark formed on the second surface, and the position adjustment unit, the first design reference deviation amount monitored by the monitoring unit, By the monitoring unit Based on the second design criteria displacement amount of vision to adjust the front and back position of the mark, it is preferable.

  According to this image reading apparatus, it is possible to accurately monitor the positional deviation between the front and back of the mark.

  Further, in the image reading apparatus according to the present invention, the position adjusting unit is read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the first scanner. When the front and back positions of the mark are adjusted based on the print position of the mark formed on the second surface of the paper, the adjustment reference for the mark that is a reference for monitoring the front and back position deviation of the mark by the monitoring unit Preferably, the position is determined.

  According to this image reading apparatus, it is possible to monitor the mark front / back positional deviation without being affected by the machine difference of each scanner.

  Further, in the image reading apparatus according to the present invention, the second scanner reads the mark formed on the sheet when the monitoring unit monitors the front / back position deviation of the mark, and the monitoring unit When monitoring the front / back position deviation of the mark formed on the paper, the adjustment reference deviation between the adjustment reference position of the mark determined by the position adjustment unit and the printing position of the mark read by the second scanner Preferably, the amount is monitored, and the position adjustment unit adjusts the front and back positions of the mark based on the adjustment reference deviation amount monitored by the monitoring unit.

  According to this image reading apparatus, it is possible to monitor the front / back position deviation of the mark particularly remarkably without being influenced by the machine difference of each scanner.

In order to achieve the above object, an image forming system according to the present invention includes an image forming unit that forms images on the front and back sides of a sheet, a first scanner that reads an image formed on the sheet, and the first scanner. A second scanner that is provided on the opposite side of the first scanner across a conveyance path for passing the paper and that reads an image formed on the paper, the image forming system comprising: Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or The printing position of the mark formed on the first surface of the document that can be read from the front and back with the same reference, read by the first scanner, and read by the second scanner A machine difference adjusting unit that adjusts a machine difference between the first scanner and the second scanner based on a printing position of a mark formed on the second surface of the original, and the machine difference adjusting unit When the difference is adjusted, a first reference position that is a reference position of a mark formed on the first surface of the sheet, and a second reference position that is a reference position of a mark formed on the second surface of the sheet. The position adjustment unit for determining the position, the first reference position determined by the position adjustment unit, and the printing amount of the mark formed on the first surface of the sheet read by the first scanner. A first reference deviation amount is monitored, and a deviation between the second reference position determined by the position adjustment unit and a printing position of a mark formed on the second surface of the sheet read by the second scanner. A monitoring unit that monitors the second reference deviation amount, which is a quantity That.
Further, in the image forming system according to the present invention, the position adjustment unit is a sheet based on the first reference deviation amount monitored by the monitoring unit and the second reference deviation amount monitored by the monitoring unit. It is preferable that feedback for adjusting a printing position when a mark is formed on the image forming unit.
Further, in the image forming system according to the present invention, the machine difference adjusting unit is read by the printing position of the mark formed on the first surface of the paper read by the first scanner and by the second scanner. It is preferable to adjust a machine difference between the first scanner and the second scanner based on a printing position of a mark formed on the first surface of the paper.
Further, in the image forming system according to the present invention, a reversing path for reversing the sheet is provided between the first scanner and the second scanner or upstream of the first scanner, When the machine difference is adjusted, the first scanner reads an image formed on a sheet that is not reversed by the reversing path, and the second scanner reads an image formed on the sheet reversed by the reversing path. It is preferable to read.
In the image forming system according to the present invention, the machine difference adjustment unit may be configured to use the machine difference based on a mark formed on the first surface of the same sheet read by the first scanner and the second scanner. It is preferable to adjust.
Further, in the image forming system according to the present invention, the machine difference adjustment unit may calculate the machine difference based on a mark formed on the first surface of different sheets read by the first scanner and the second scanner. It is preferable to adjust.
Further, in the image forming system according to the present invention, the machine difference adjustment unit includes a printing position of a mark formed on the first surface of the document read by the first scanner and a document read by the second scanner. It is preferable that the machine difference between the first scanner and the second scanner is adjusted based on the printing position of the mark formed on the second surface.
In the image forming system according to the present invention, the position adjustment unit may be configured such that the first reference position is based on a print position of a mark formed on the document when the machine difference is adjusted by the machine difference adjustment unit. And determining the second reference position.

  According to this image forming system, as in the case of the image reading apparatus, it is possible to easily detect sudden front / back position deviation of an image while accurately reading the front / back position of an image formed on a sheet at low cost. it can.

  Further, according to this image forming system, it is possible to provide a low-cost feedback system as a whole system.

  In order to achieve the above object, a program according to the present invention includes a first scanner that reads an image formed on a sheet, a downstream side of the first scanner, and a conveyance path that passes the sheet. A computer that controls an image reading device provided on the opposite side of the first scanner and that reads an image formed on the paper is formed on the first surface of the paper read by the first scanner. On the basis of the printed position of the marked mark and the printed position of the mark formed on the first surface of the paper read by the second scanner, or by the same reference from the front and back, read by the first scanner. The printing position of the mark formed on the first surface of the document from which the positional relationship can be read, and the printing of the mark formed on the second surface of the document read by the second scanner The difference between the first scanner and the second scanner is adjusted based on the position, and when the difference is adjusted by the difference adjustment unit, the difference is formed on the first surface of the sheet. A position adjusting unit that determines a first reference position that is a reference position of a mark to be printed and a second reference position that is a reference position of a mark formed on the second surface of the paper, and the position adjusting unit determines the position. A first reference deviation amount, which is a deviation amount between the first reference position and a printing position of a mark formed on the first surface of the paper read by the first scanner, is monitored by the position adjustment unit; A monitoring unit that monitors a second reference deviation amount that is a deviation amount between the determined second reference position and a printing position of a mark formed on the second surface of the sheet read by the second scanner; It is intended to function as.

  According to this program, as in the case of the image reading apparatus, it is possible to easily detect a sudden front / back position shift of an image while accurately reading the front / back position of an image formed on a sheet at a low cost.

  According to the present invention, it is possible to easily detect a sudden front / back position shift of an image while accurately reading the front / back position of an image formed on a sheet at low cost.

1 is a diagram illustrating an example of an overall configuration of an image forming system 1 in Embodiment 1 of the present invention. 1 is a diagram illustrating a configuration example of an image forming apparatus 5 according to a first embodiment of the present invention. It is a figure which shows the structural example of the image reading apparatus 7 in Embodiment 1 of this invention. It is a figure which shows the function structural example of the control part 51 in Embodiment 1 of this invention. It is a figure which shows an example of the mark A formed on the paper P in Embodiment 1 of the present invention. FIG. 6 is a diagram illustrating an example in which the same sheet P is transported in a transport path 700 of the sheet P according to Embodiment 1 of the present invention. It is a flowchart explaining the example of control in Embodiment 1 of this invention. It is a figure which shows the example of front-and-back position adjustment of the mark A in Embodiment 1 of this invention. FIG. 5 is a diagram illustrating an example in which different paper P is transported in a paper P transport path 700 according to Embodiment 1 of the present invention. It is a figure which shows an example of the conveyance path | route 700 of the paper P in Embodiment 2 of this invention. It is a flowchart explaining the example of control in Embodiment 2 of this invention. It is a figure which shows the example of front-and-back position adjustment of the mark A in Embodiment 2 of this invention. FIG. 10 is a diagram illustrating an example in which different paper P is transported in a paper P transport path 700 according to Embodiment 3 of the present invention. It is a flowchart explaining the example of control in Embodiment 3 of this invention. It is a figure which shows the example of front / back position adjustment of the mark A in Embodiment 3 of this invention. FIG. 10 is a diagram illustrating an example in which the same paper P is transported in a paper P transport path 700 according to Embodiment 3 of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, but the present invention is not limited to the following embodiments.

Embodiment 1. FIG.
FIG. 1 is a diagram showing an example of the overall configuration of an image forming system 1 in Embodiment 1 of the present invention. As shown in FIG. 1, the image forming system 1 includes a paper feeding device 3, an image forming device 5, an image reading device 7, and a paper discharging device 8. The paper feeding device 3 feeds the paper P to the image forming device 5. The image forming apparatus 5 forms an image on the paper P fed from the paper feeding device 3. The image reading device 7 reads the paper P on which an image is formed by the image forming device 5 and executes various processes. The paper discharge device 8 includes a paper discharge tray 9 and discharges the paper P conveyed from the image reading device 7 to the paper discharge tray 9.

  Next, the image forming apparatus 5 will be specifically described. FIG. 2 is a diagram illustrating an example of an internal configuration of the image forming apparatus 5 according to the first embodiment. As shown in FIG. 2, the image forming apparatus 5 is an example of a color copying machine, acquires image information by reading a color image formed on a document T, and superimposes colors based on the acquired image information. A device for forming a color image. The image forming apparatus 5 is suitable for being applied to a color printer or facsimile apparatus, a multifunction machine of these, etc. in addition to a color copying machine.

  The image forming apparatus 5 includes an image forming apparatus main body 11. A color image reading unit 12 and an automatic document feeder 14 are disposed on the upper part of the image forming apparatus main body 11. The image forming apparatus main body 11 includes a control unit 41, an image processing unit 43, an image forming unit 60, a paper feeding unit 20, and a conveyance unit 30, which will be described in detail later.

  Next, the automatic document feeder 14 will be described. The automatic document feeder 14 is provided on the image reading unit 12 and performs an operation of automatically feeding one or a plurality of documents T in the automatic feeding mode. Here, the automatic paper feed mode is an operation of feeding a document T placed on the automatic document feeder 14 and reading an image printed on the document T.

  Specifically, the automatic document feeder 14 includes a document placement unit 141, a roller 142 a, a roller 142 b, a roller 143, a roller 144, a reversing unit 145, and a paper discharge tray 146. On the document placing portion 141, one or a plurality of documents T are placed. A roller 142 a and a roller 142 b are provided on the downstream side of the document placing portion 141. A roller 143 is provided on the downstream side of the rollers 142a and 142b. Further, the automatic document feeder 14 includes a positioning detector 81 on the outer peripheral side of the roller 143.

  When the automatic paper feeding mode is selected, the document T fed out from the document placement unit 141 is rotated by a roller 143 and conveyed. Note that when the document T is placed on the document placement unit 141 and the automatic paper feeding mode is selected, the recording surface of the document T may be in an upward state.

  In addition, the original T is read by the image reading unit 12, then conveyed by the roller 144, and discharged to the discharge tray 146. The automatic document feeder 14 can cause the image reading unit 12 to read not only the recording surface of the document T but also the back side of the recording surface of the document T by conveying the document T to the reversing unit 145.

  Next, the positioning detection unit 81 will be described. The positioning detection unit 81 detects the document T on which an image is printed. The positioning detection unit 81 is configured by, for example, a reflective photosensor. When the document T is detected, the positioning detection unit 81 rises an output signal. When the document T is no longer detected, the output signal falls, and the result is transmitted to the control unit 41. That is, the output signal maintains a constant value during the period in which the document T passes the positioning detection unit 81.

  Next, the image reading unit 12 will be described. The image reading unit 12 performs an operation of reading a color image formed on the document T, that is, a color image printed on the document T. The image reading unit 12 includes a one-dimensional image sensor 128. In addition to the image sensor 128, the image reading unit 12 includes a first platen glass 121, a second platen glass 122, a light source 123, mirrors 124, 125, and 126, an imaging optical unit 127, and an optical (not shown). A drive unit is provided.

  The light source 123 irradiates the document T with light. An optical drive unit (not shown) relatively moves the document T or the image sensor 128 in the sub-scanning direction. Here, the sub-scanning direction is a direction orthogonal to the main scanning direction when the arrangement direction of the plurality of light receiving elements constituting the image sensor 128 is the main scanning direction.

  Accordingly, the document T is conveyed by the automatic document feeder 14, and the image on the one side or both sides of the document T is scanned and exposed by the optical system of the image reading unit 12. Next, incident light reflecting the image reading operation is read by the image sensor 128. In the Plato mode, the image sensor 128 outputs an RGB color system image reading signal Sout obtained by reading the document T. Here, the platen mode is printed on a document T placed on a platen glass such as the first platen glass 121 and the second platen glass 122 by driving an optical drive unit (not shown). This is an operation that automatically reads an image.

  Next, the image sensor 128 will be specifically described. As the image sensor 128, a three-line color CCD imaging device is used. The image sensor 128 is configured by arranging a plurality of light receiving element arrays in the main scanning direction. Specifically, each of the red (R), green (G), and blue (B) light detection reading sensors divides pixels at different positions in the sub-scanning direction orthogonal to the main scanning direction. Then, the optical information of each of the R color, G color, and B color is read simultaneously. For example, in the automatic paper feed mode, when the document T is reversed U-shaped by the roller 143, the image sensor 128 reads the surface of the document T and outputs an image reading signal Sout.

  More specifically, the image sensor 128 photoelectrically converts incident light, and is connected to the image processing unit 43 via the control unit 41. The analog image reading signal Sout photoelectrically converted by the image sensor 128 is subjected to analog processing, A / D conversion, shading correction, image compression processing, scaling processing, and the like in the image processing unit 43. As a result, the image reading signal Sout becomes digital image data including an R color component, a G color component, and a B color component. Based on the three-dimensional color information conversion table, the image processing unit 43 converts the image data, that is, RGB code, into Y (yellow), M (magenta), C (cyan), and K (black) color image data, that is, , Dy, Dm, Dc, Dk. The image processing unit 43 transfers the converted image data to the LED writing units 611Y, 611M, 611C, and 611K included in the image forming unit 60.

  Next, details of the image forming unit 60 will be described. The image forming unit 60 uses electrophotographic process technology and forms an intermediate transfer type color image. The image forming unit 60 employs a vertical tandem system.

  Specifically, the image forming unit 60 forms a color image based on the image data transferred from the image processing unit 43, that is, Dy, Dm, Dc, Dk. The image forming unit 60 includes image forming units 601Y, 601M, 601C, and 601K for each color, an intermediate transfer unit 620, and a fixing unit 630 that fixes a toner image.

  Next, the image forming unit 601Y will be described. The image forming unit 601Y forms a Y (yellow) color image. The image forming unit 601Y includes a photosensitive drum 613Y, a charging unit 614Y, an LED writing unit 611Y, a developing unit 612Y, and a cleaning unit 616Y.

  The photosensitive drum 613Y forms a Y-color toner image. The charging unit 614Y is disposed around the photosensitive drum 613Y and uniformly charges the surface of the photosensitive drum 613Y to a negative polarity by corona discharge. The LED writing unit 611Y irradiates the photosensitive drum 613Y with light corresponding to the image of the Y color component. The developing unit 612Y visualizes the electrostatic latent image and forms a toner image by attaching Y color component toner to the surface of the photosensitive drum 613Y. The cleaning unit 616Y removes transfer residual toner remaining on the surface of the photosensitive drum 613Y after the primary transfer.

  Since each of the image forming units 601M, 601C, and 601K has the same configuration and function as the image forming unit 601Y except that the color of the image to be formed is different, the description thereof is omitted.

  Note that the image forming units 601Y, 601M, 601C, and 601K are collectively referred to as an image forming unit 601. The LED writing units 611Y, 611M, 611C, and 611K are collectively referred to as the LED writing unit 611. The developing units 612Y, 612M, 612C, and 612K are collectively referred to as the developing unit 612. The photosensitive drums 613Y, 613M, 613C, and 613K are collectively referred to as the photosensitive drum 613. The charging units 614Y, 614M, 614C, and 614K are collectively referred to as a charging unit 614. The cleaning units 616Y, 616M, 616C, and 616K are collectively referred to as a cleaning unit 616.

  Next, the intermediate transfer unit 620 will be described. The intermediate transfer unit 620 includes an intermediate transfer belt 621, primary transfer rollers 622Y, 622M, 622C, and 622K, a secondary transfer roller 623, a belt cleaning device 624, and the like.

  The intermediate transfer belt 621 is composed of an endless belt, and is stretched in a loop by a plurality of support rollers. At least one of the plurality of support rollers is composed of a driving roller, and the other is composed of a driven roller. For example, it is preferable that the support roller disposed downstream of the K component primary transfer roller 622K in the belt traveling direction is a drive roller. As the drive roller rotates, the intermediate transfer belt 621 travels at a constant speed in the arrow Z direction.

  The primary transfer rollers 622Y, 622M, 622C, and 622K are disposed on the inner peripheral surface side of the intermediate transfer belt 621 so as to face the photosensitive drums 613 of the respective color components. The primary transfer rollers 622Y, 622M, 622C, and 622K are pressed against the photosensitive drums 613Y, 613M, 613C, and 613K with the intermediate transfer belt 621 interposed therebetween. As a result, a primary transfer nip for transferring a toner image from the photosensitive drums 613Y, 613M, 613C, and 613K to the intermediate transfer belt 621 is formed.

  The primary transfer rollers 622Y, 622M, 622C, and 622K are collectively referred to as the primary transfer roller 622.

  The secondary transfer roller 623 is disposed on the outer peripheral surface side of the intermediate transfer belt 621 so as to face one of the plurality of support rollers. The support roller disposed to face the intermediate transfer belt 621 is called a backup roller. The secondary transfer roller 623 is pressed against the backup roller with the intermediate transfer belt 621 interposed therebetween, so that a secondary transfer nip for transferring the toner image from the intermediate transfer belt 621 to the paper P is formed.

  When the intermediate transfer belt 621 passes through the primary transfer nip, the toner image on the photosensitive drum 613 is primarily transferred to the intermediate transfer belt 621 in order. Specifically, a primary transfer bias is applied to the primary transfer roller 622, and an electric charge having a polarity opposite to that of the toner is applied to the back side of the intermediate transfer belt 621, that is, the side in contact with the primary transfer roller 622. Is electrostatically transferred to the intermediate transfer belt 621.

  Thereafter, when the paper P passes through the secondary transfer nip, the toner image on the intermediate transfer belt 621 is secondarily transferred to the paper P. Specifically, a secondary transfer bias is applied to the secondary transfer roller 623, and a charge having a polarity opposite to that of the toner is applied to the back side of the paper P, that is, the side in contact with the secondary transfer roller 623. The image is electrostatically transferred to the paper P. The sheet P to which the toner image is transferred is conveyed toward the fixing unit 630.

  The belt cleaning device 624 includes a belt cleaning blade that is in sliding contact with the surface of the intermediate transfer belt 621. The belt cleaning device 624 removes transfer residual toner remaining on the surface of the intermediate transfer belt 621 after the secondary transfer.

  In the intermediate transfer unit 620, instead of the secondary transfer roller 623, a secondary transfer belt (not shown) is looped around a plurality of support rollers including the secondary transfer roller 623, a so-called belt. A secondary transfer unit of the formula may be employed.

  Next, the fixing unit 630 will be described. The fixing unit 630 includes a heating roller 631, a pressure roller 632, a heating unit 633, and a temperature detection unit 83, and fixes the toner image transferred by the image forming unit 60 to the paper P.

  Specifically, the heating unit 633 is provided inside the heating roller 631 and intermittently heats the heating roller 631. The pressure roller 632 is disposed to face the heating roller 631 and pressurizes the heating roller 631. The temperature detection unit 83 is provided around the heating roller 631 and detects the temperature of the heating roller 631. The sampling period of the temperature detector 83 is, for example, 100 ms.

  In the fixing unit 630, the heating unit 633 heats the heating roller 631 according to the detection result of the temperature detection unit 83 that detects the temperature of the heating roller 631. The fixing unit 630 forms a fixing nip between the heating roller 631 and the pressure roller 632 by bringing the heating roller 631 and the pressure roller 632 into pressure contact with each other.

  The fixing unit 630 fixes the transferred toner image on the paper P through the action of pressure by the pressure roller 632 and heat of the heating roller 631. An image is printed on the paper P fixed by the fixing unit 630. The paper P on which the image is printed is discharged to the outside by the paper discharge roller 304 and is conveyed to the image reading device 7, for example. The paper P on which the image is printed may be stacked on the paper discharge tray 305 without being conveyed to the image reading device 7.

  Next, the paper feeding unit 20 will be described. The paper feed unit 20 includes a paper feed cassette 200, a feed roller 201, and the like. The paper feed cassette 200 stores paper P. The delivery roller 201 takes in the paper P stored in the paper feed cassette 200 and sends it out to the transport unit 30.

  Next, the conveyance unit 30 will be described. The transport unit 30 includes a transport path 300 and transports the paper P along the transport path 300. The conveyance path 300 includes a paper feed roller 302A, conveyance rollers 302B, 302C, and 302D, a registration roller 303, and the like.

  The conveyance path 300 conveys the paper P fed from the paper feeding unit 20 to the image forming unit 60. When image formation is also performed on the back surface of the paper P, after the image formation is performed on the front surface of the paper P, the paper P is separated by the branching unit 306 by the circulation paper path 307A, the reverse conveyance path 307B, The paper is conveyed in the order of the paper feed conveyance path 307C.

  Next, the control system will be described. The image forming apparatus 5 executes various processes via the control unit 41. For example, the image reading signal Sout output from the image reading unit 12 is transmitted to an image memory (not shown) or the image processing unit 43 via the control unit 41. The image memory is composed of, for example, a hard disk.

  Specifically, the control unit 41 is configured mainly with a CPU, a ROM, a RAM, and an I / O interface (not shown). In the control unit 41, the CPU reads out various programs corresponding to the processing contents from the ROM or a storage unit (not shown), expands the program in the RAM, and cooperates with the expanded various programs, thereby controlling the operation of each unit of the image forming apparatus 5. Control.

  That is, the control unit 41 controls the operation of the image forming apparatus 5 and can be realized by a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface (not shown). Various functions are implement | achieved when the control part 41 runs a predetermined | prescribed control program.

  Next, the image reading device 7 will be specifically described. FIG. 3 is a diagram illustrating a configuration example of the image reading apparatus 7 according to the first embodiment of the present invention. FIG. 4 is a diagram illustrating a functional configuration example of the control unit 51 according to the first embodiment of the present invention.

  The image reading device 7 is arranged on the downstream side of the image forming device 5 and reads an image printed on one side or both sides of the paper P. The image reading device 7 obtains an image correction amount based on the reading result such as the color, position, and magnification of the image printed on the paper P, and feeds back the obtained image correction amount to the image forming device 5.

  The image reading device 7 includes a control unit 51, a first scanner 701 a, a second scanner 701 b, a colorimeter 703, calibration units 705 a to 705 c, a conveyance roller 731, and a conveyance path 700. The transport path 700 is a path through which the paper P supplied from the image forming apparatus 5 is passed, and the paper P is transported by driving the transport roller 731.

  For example, when the image reading device 7 receives the paper P supplied from the image forming device 5, the image reading device 7 causes the first scanner 701 a, the second scanner 701 b, or the colorimeter 703 to detect an image formed on the paper P. The image detection result is output to the control unit 51 of the image reading device 7.

  The control unit 51 controls the operation of the image reading device 7 and can be realized by a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface (not shown). When the control unit 41 executes a predetermined control program, various functions including a position adjustment unit 511, a monitoring unit 513, and a machine difference adjustment unit 515 are realized as shown in FIG. The control unit 51 executes various processes based on the image detection result, and transmits the execution result to the control unit 41 of the image forming apparatus 5.

  The position adjustment unit 511 adjusts the front and back positions of the mark A based on the print position of the mark A read by at least one of the first scanner 701a and the second scanner 701b. Here, the mark A formed on the paper P will be described.

  FIG. 5 is a diagram illustrating an example of the mark A formed on the paper P in Embodiment 1 of the present invention. As shown in FIG. 5, the mark A is a crosshair, and is used for detecting the positional deviation between the front and back sides. The mark A is formed at a position T1 away from the corner of the paper P in the vertical and horizontal directions. Since the sheet P has four corners, four marks A are also formed. However, the marks may not be formed on all the corners, and it is only necessary that the front / back position deviation can be detected by the marks A. Further, the mark A may not be a crosshair.

  Returning to FIG. The monitoring unit 513 monitors the front / back position deviation of the mark A based on the front / back position of the mark A adjusted by the position adjustment unit 511. The machine difference adjustment unit 515 determines whether the first scanner 701a and the second scanner 701b are based on the printing position of the mark A read by the first scanner 701a and the printing position of the mark A read by the second scanner 701b. Adjust the machine difference.

  When the machine difference between the first scanner 701a and the second scanner 701b is adjusted by the machine difference adjusting unit 515, the position adjusting unit 511 adjusts the mark A serving as a reference for monitoring the positional deviation of the front and back of the mark A by the monitoring unit 513. Determine the adjustment reference position.

  The first scanner 701a and the second scanner 701b are arranged to face the paper P passing through the transport path 700, and read an image printed on the paper P. The first scanner 701a scans the back surface of the paper P, and the reading result is used for checking, for example, whether the image printed on the paper P is misaligned or whether there is an unexpected image. On the other hand, the second scanner 701b reads the surface of the paper P and performs an operation of reading an image printed on the paper P, for example, a patch (not shown). Note that the first scanner 701a and the second scanner 701b are referred to as the scanner 701 when they are not particularly distinguished.

  Note that the image reading apparatus 7 is operated by either an inline method or an offline method.

  The in-line method is configured to directly feed an image-formed sheet P supplied from the image forming apparatus 5 to the image reading apparatus 7. On the other hand, the offline system is not configured to feed the image-formed paper P supplied from the image forming apparatus 5 directly to the image reading apparatus 7, but the image forming apparatus 5, the image reading apparatus 7, and the like. Is a system configured independently of each other. Here, the following description will be given on the premise of the inline method, but an offline method may be used.

  The colorimeter 703 is located on the downstream side of the scanner 701 and is disposed at a position facing the paper P that passes through the transport path 700. For example, the colorimeter 703 guarantees the absolute value of the color of the image formed on the paper P by measuring the color of the patch among the images formed on the paper P.

  Specifically, the colorimeter 703 emits visible light from a visible light source (not shown) toward the patch, acquires a spectral spectrum of the reflected light of the visible light reflected by the calibration unit 705c, and acquires the acquired spectrum. Based on the spectrum, an operation for a predetermined color system is executed, and the color of the patch is derived.

  The color measurement result of the patch is generated as numerical data expressed by a predetermined color system, for example, Lab color space data or XYZ color space data, that is, a color measurement value, and is output to the control unit 51 or the control unit 41. The

  The colorimetric range of the colorimeter 703, that is, the viewing angle, is set to be narrower than the reading range of the scanner 701 and narrower than the width of the patch along the paper width direction. Specifically, the lens unit that acquires the reflected light of the patch is, for example, about 4 mm.

  As described above, the colorimeter 703 performs colorimetry only in a certain viewing angle range, and therefore can reproduce color information with higher accuracy than the scanner 701.

  The control unit 51 corrects the color information of the patches read by the scanner 701 based on the colorimetric values of the patches measured by the colorimeter 703. Specifically, the control unit 51 associates the color information of the patch measured by the colorimeter 703 with the color information of the patch read by the scanner 701. If the color information of the patch by the colorimeter 703 and the color information of the patch by the scanner 701 are associated with each other, the color measurement result of the colorimeter 703 can be reflected in the reading result of the scanner 701, and accurate A correction amount is obtained.

  The image processing unit 43 optimizes an image to be formed by the image forming unit 60 based on the correction amount calculated by the control unit 51. The image optimization processing executed by the image processing unit 43 includes front / back position adjustment, density adjustment, color adjustment, and the like of the image printed on the paper P.

  That is, the image processing unit 43 corrects the color, position, or magnification of the image formed on the paper P according to the reading result of the paper P of the image reading device 7. Specifically, the image processing unit 43 corrects an image formed on the paper P based on the corrected color information. The image processing unit 43 issues a command to form an image on the paper P to the image forming unit 60 based on the correction result.

  The calibration units 705a and 705b are arranged at positions facing the scanner 701, and reflect the irradiation light irradiated on the paper P when reading an image.

  Next, the conveyance path 700 will be specifically described. FIG. 6 is a diagram illustrating an example in which the same paper P is transported in the paper P transport path 700 according to the first embodiment of the present invention. As shown in FIG. 6, an inversion path 751 a is provided along the transport path 700 between the first scanner 701 a and the second scanner 701 b. The reversing path 751a reverses the paper P read by the first scanner 701a on the upstream side and conveys it to the second scanner 701b on the downstream side.

  Therefore, if the paper P passes through the reverse path 751a, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the first surface P_1f of the paper P.

  Therefore, the conveyance path 700 in FIG. 6 can read the mark A formed on the same surface of the same paper P by the first scanner 701a and the second scanner 701b.

  If the paper P does not pass through the reverse path 751a, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the second surface P_2f of the paper P.

  Therefore, the conveyance path 700 in FIG. 6 can read the marks A formed on the different surfaces of the paper P by the first scanner 701a and the second scanner 701b.

  The first surface P_1f of the paper P means either one of the front surface or the back surface of the paper P, and the second surface P_2f of the paper P means any of the front surface or the back surface of the paper P. Or the other. The same applies to the following description.

  In the conveyance path 700 of FIG. 6, the machine difference adjustment unit 515 adjusts the machine difference of each scanner 701 based on the mark A formed on the same surface of the paper P. In the transport path 700 of FIG. 6, when the monitoring unit 513 monitors the front / back position deviation of the mark A formed on the paper P, the paper in the adjustment reference position of the mark A determined by the position adjustment unit 511. First adjustment reference position of the first adjustment reference position of the mark A formed on the first surface P_1f of P and the print position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a. Monitor the amount of deviation. In the transport path 700 of FIG. 6, when the monitoring unit 513 monitors the front / back position deviation of the mark A formed on the paper P, the paper in the adjustment reference position of the mark A determined by the position adjustment unit 511. The second adjustment reference position of the mark A formed on the second surface P_2f of P and the print position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b. Monitor the amount of deviation.

  Further, in the transport path 700 of FIG. 6, the position adjustment unit 511 performs mark A based on the first adjustment reference deviation amount monitored by the monitoring unit 513 and the second adjustment reference deviation amount monitored by the monitoring unit 513. Adjust the front and back position.

  The adjustment of the front and back positions of the mark A only needs to be performed as a result, and the specific adjustment process is not limited. For example, the reading time of each scanner 701 may be adjusted, and a correction amount based on the adjustment result may be fed back to the image forming apparatus 5. Further, for example, the correction amount based on the reading result of each scanner 701 is fed back to the image forming apparatus 5, and the image forming apparatus 5 actually adjusts the printing position of the mark A when forming the mark A on the paper P. May be.

  Next, a control example of the control unit 51 in the transport path 700 of FIG. 6 will be described. FIG. 7 is a flowchart illustrating an example of control according to the first embodiment of the present invention.

  In step S11, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S12, the second scanner 701b reads the mark A formed on the first surface P_1f of the paper P. In step S13, the machine difference between the first scanner 701a and the second scanner 701b is adjusted.

  As mentioned above, the process of step S11-S13 is a machine difference adjustment process.

  In step S14, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S15, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S16, the adjustment reference position is determined based on the printing position of the mark A formed on the first surface P_1f of the paper P and the printing position of the mark A formed on the second surface P_2f of the paper P.

  The processing in steps S14 to S16 is processing for determining the adjustment reference position that is performed when the front / back position deviation of the paper P is monitored.

  In step S17, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S18, it is determined whether or not there is a deviation between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f among the adjustment reference positions. If it is determined that there is a difference between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f of the adjustment reference positions, the process proceeds to step S19, and in step S19 The shift of the first surface P_1f is adjusted, and the process proceeds to step S20. On the other hand, when it is determined that there is no deviation between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f among the adjustment reference positions, the process proceeds to step S20.

  In step S20, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S21, it is determined whether or not there is a deviation between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f among the adjustment reference positions. If it is determined that there is a deviation between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f of the adjustment reference positions, the process proceeds to step S22, and in step S22 The deviation of the second surface P_2f is adjusted, and the process proceeds to step S23. On the other hand, if it is determined that there is no deviation between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f among the adjustment reference positions, the process proceeds to step S23.

  In step S23, it is determined whether or not the monitoring is ended. If it is determined that the monitoring is to be terminated, the process is terminated. On the other hand, when it is determined that the monitoring is not ended, the process returns to step S17.

  As described above, the processes in steps S17 to S23 are the monitoring process and the position adjustment process.

  There are conditions that affect the occurrence of misalignment between the front and back sides of printing. The first is environmental conditions, which are the temperature and humidity of the printing place. Specifically, there are high-temperature and high-humidity environments, low-temperature and low-humidity environments, and general environments. In a hot and humid environment, the moisture content of the paper P tends to increase, and printing position deviation tends to occur. In a low-temperature and low-humidity environment, the paper P is likely to slip and a printing position shift is likely to occur. In the general environment, the paper P is stable, and the printing position is unlikely to occur.

  In the following description, a hot and humid environment is referred to as an HH environment, a low temperature and low humidity environment is referred to as an LL environment, and a general environment is referred to as an NN environment.

  The second is the paper P to be printed. The paper P includes high basis weight paper, large size paper, thick paper, and the like. The high basis weight paper is a paper having a large basis weight, and there are many thick papers P, the moisture content is likely to change, and the printing position deviation is likely to occur. Large-size paper has a large print image, and accordingly, a print position shift due to the print magnification tends to occur. Thick paper is thick paper with respect to the basis weight, and its water content is likely to change, and print position deviation is likely to occur.

  The third is deterioration of machine durability of the printing press main body. For example, if each part of the image forming apparatus 5 is mechanically deteriorated due to long-term use, a printing position shift is likely to occur.

  The period for monitoring the front and back positions is set by environmental conditions or the user. For example, when printing in an HH environment or LL environment, or printing on a thick paper P, it is preferable to monitor each time printing is performed. That is, it is a short-term monitoring, and it is estimated that sudden front / back position misalignment is likely to occur.

  Further, for example, when the mechanical wear of the printing press main body becomes severe, it is preferable to monitor every 6 hours. That is, it is a case of monitoring during the middle period, and it is estimated that there is a possibility that a sudden front / back position deviation may occur.

  For example, when printing in an NN environment or printing on standard recommended paper, it is preferable to monitor in the morning once a day. That is, it is a case of long-term monitoring, and it is estimated that sudden front-back displacement is unlikely to occur.

  Next, machine difference adjustment and front / back position deviation adjustment will be specifically described. FIG. 8 is a diagram illustrating an example of adjusting the front and back positions of the mark A according to the first embodiment of the present invention. The 0th sheet in FIG. 8 corresponds to the paper P for adjusting the difference between the machines before monitoring, and the first sheet corresponds to the monitoring sheet P performed after the adjustment of the errors.

  Specifically, for the 0th sheet, machine difference adjustment of each scanner 701 performed before monitoring the front / back position deviation of the mark A formed on the sheet P is performed. For example, the printing position of the mark A on the first surface P_1f read by the second scanner 701b is adjusted according to the printing position of the mark A read by the first scanner 701a.

  In the first sheet, a process for determining an adjustment reference position for use in monitoring is performed. In the second and subsequent sheets, the front / back position deviation of the mark A is monitored based on the adjustment reference position determined in the first sheet. For example, on the nth sheet, the printing position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted in accordance with the second adjustment reference position determined on the first sheet.

  Even if the printing position of the mark A matches the design value, when the adjustment reference position is determined for the first sheet, the adjustment is performed so that there is no difference from the adjustment reference position determined for the first sheet.

  In the case of the reversing path 751a provided in the transport path 700 of FIG. 6, the same paper P is read by each scanner 701, but the present invention is not limited to this. FIG. 9 is a diagram illustrating an example in which different paper P is transported in the paper P transport path 700 according to the first embodiment of the present invention.

  The conveyance path 700 of FIG. 9 is provided with a reverse path 751b on the upstream side of the first scanner 701a. Accordingly, the reversing path 751b in FIG. 9 causes the first scanner 701a to read the sheet P ′ with the first side P′_1f face-up, and the second scanner 701b to have the first side P_1f face-down. P can be read. Accordingly, the reversing path 751b in FIG. 9 can cause each scanner 701 to read the same surface of different sheets P and P ′, that is, the first surface P_1f and the first surface P′_1f. In addition, when not distinguishing any of the inversion paths 751a and 751b, the inversion paths 751 are referred to.

  As described above, the image reading device 7 adjusts the front and back positions of the mark A based on the print positions of the marks A respectively formed on the front and back sides of the paper P read by at least one of the first scanner 701a and the second scanner 701b. .

  For example, if the front / back position of the mark A is adjusted based on the printing position of the mark A read by the first scanner 701a, the front / back position deviation of the mark A due to the first scanner 701a alone is adjusted. Further, for example, if the front / back position of the mark A is adjusted based on the print position of the mark A read by the second scanner 701b, the front / back position deviation of the mark A due to the second scanner 701b alone is adjusted. . Further, for example, if the front and back positions of the mark A are adjusted based on the print position of the mark A read by each of the first scanner 701a and the second scanner 701b, the mark A caused by the machine difference of each scanner 701 is adjusted. The front / back displacement is adjusted.

  The image reading device 7 monitors the front / back position deviation of the mark A based on the adjusted front / back position of the mark A. For example, if monitoring is performed based on the front and back positions of the mark A adjusted based on the reading result of the first scanner 701a, even if there is a machine difference between the first scanner 701a and the second scanner 701b, The front / back position deviation of the mark A can be monitored in a state where there is no influence.

  Further, for example, if monitoring is performed based on the front and back positions of the mark A adjusted based on the reading result of the second scanner 701b, even if there is a machine difference between the second scanner 701b and the first scanner 701a, the machine The front / back position deviation of the mark A can be monitored in a state where there is no difference.

  Further, for example, if monitoring is performed based on the front and back positions of the mark A adjusted based on the respective reading results of the first scanner 701a and the second scanner 701b, the difference between the first scanner 701a and the second scanner 701b. The front / back position deviation of the mark A can be monitored in a state where is adjusted.

  In any case, the influence of the machine difference of each scanner 701 can be eliminated without performing mechanical adjustment.

  Further, since the front / back position deviation of the mark A can be detected, the front / back position deviation of the image formed with the mark A as a reference can be detected. The front / back position deviation of the mark A can be easily detected without being overlooked because the detection target is simple and limited as compared with the case where only the front / back position deviation of the image is detected. Therefore, it is possible to easily detect a sudden front / back position shift of the image.

  In other words, the image reading device 7 determines the front and back positions of the mark A based on the print positions of the marks A respectively formed on the front and back sides of the paper P read by at least one of the first scanner 701a and the second scanner 701b. By adjusting and monitoring the front / back position of the mark A based on the adjusted front / back position, the influence of the machine difference of each scanner 701 can be eliminated without mechanical adjustment. Since the front / back position deviation of A can be detected, the sudden front / back position deviation of the image can be easily detected while accurately reading the front / back position of the image formed on the paper P at low cost.

  In the image reading device 7, the first scanner 701a and the second scanner 701b are based on the printing position of the mark A read by the first scanner 701a and the printing position of the mark A read by the second scanner 701b. When the machine difference is adjusted, the adjustment reference position of the mark A, which is a reference for monitoring the displacement of the front and back positions of the mark A, is determined. Therefore, it is possible to monitor the front / back position deviation of the mark A by using both the first scanner 701a and the second scanner 701b. Therefore, since the mark A formed on the front and back sides of the paper P can be monitored at the same time by one transport, if the front and back positions of the mark A are misaligned, the mark A can be compared with the case where the single scanner 701 transports the mark A twice. It is possible to reduce the time required to detect the front / back position deviation of A.

  Further, in the image reading device 7, the machine difference of each scanner 701 is adjusted based on the mark A formed on the same surface of the paper P, so that the mark A read by each scanner 701 is formed on the same surface. Therefore, the same comparison object is compared, and the machine difference of each scanner 701 can be accurately detected.

  Further, in the image reading device 7, the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a and the adjustment reference of the mark A formed on the first surface P_1f of the paper P. The first adjustment reference deviation amount with respect to the position is monitored, and the print position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b and the second surface P_2f of the paper P are formed. The second adjustment reference deviation amount with respect to the adjustment reference position of the mark A is monitored, and the front and back positions of the mark A are adjusted based on the first adjustment reference deviation amount and the second adjustment reference deviation amount.

  Therefore, since the front / back position of the mark A is adjusted based on the relative front / back position deviation of the mark A, the front / back position deviation of the mark A can be monitored at a low cost.

  As described above, according to the present embodiment, it is possible to monitor the front / back position deviation of the mark A in a state where there is no influence of the difference between the scanners 701. Therefore, the high-precision component accuracy and high-precision mounting position accuracy required when mechanically adjusting the component accuracy, the mounting position accuracy, and the like are not required. For this reason, the image forming system 1 can be formed at low cost.

  The machine difference between the scanners 701 is caused by various factors such as individual lens differences, lens mounting position variations, or scanner 701 mounting position variations. In particular, the individual lens difference is based on lens distortion, and a deviation in magnification or partial magnification in the reading main scanning direction occurs. Therefore, making it possible to detect the front / back position deviation of the mark A without being affected by the machine difference between the scanners 701 contributes to a significant cost reduction of the entire system when the image forming system 1 is constructed. Become.

  Further, when the image forming apparatus 5 performs double-sided printing, even when the print setting is not changed, the front / back position deviation of the mark A or the image position deviation due to the front / back position deviation of the mark A occurs. There is. Such a shift is abrupt because it occurs due to environmental conditions such as temperature and humidity of the printing place or deterioration of mechanical durability. Therefore, conventionally, the front and back positions of the mark A are measured at regular intervals. However, side effects due to the frequency of measuring the front and back positions of the mark A also occur.

  For example, if the front / back position measurement frequency of the mark A is increased, the front / back position deviation of the mark A is detected at an early stage, but it takes much time, so the productivity of the entire system is lowered. On the other hand, if the frequency of measuring the front and back positions of the mark A is lowered, it may take time for production, but there is a possibility that the front and back position deviation of the mark A may not be detected. The output is wasteful and increases costs.

  Therefore, if the front / back position deviation of the mark A is monitored as in the present embodiment, it is possible to easily detect the front / back position deviation of the mark A due to a change in environmental conditions, thereby reducing the cost of the entire system. Can be made.

  In other words, the image forming system 1 includes the image reading device 7 and the image forming device 5, so that the front and back positions of the image formed on the paper P can be obtained at a low cost as in the case of the image reading device 7. It is possible to easily detect a sudden front / back position shift of an image while accurately reading the image.

  Further, since the image forming system 1 can easily detect the front / back position deviation of the output product of the image forming apparatus 5 by the image reading device 7 at a low cost, it is possible to provide a low-cost feedback system as a whole system.

  In this way, according to the image reading apparatus 7 according to the present embodiment, the image forming apparatus 5 forms the marks A on the front and back sides of the paper P, and the first scanner 701a and the first scanner 701a for reading the marks A. An image reading device 7 provided with a second scanner 701b for reading the mark A, and at a print position of the mark A read by at least one of the first scanner 701a and the second scanner 701b. A position adjustment unit 511 that adjusts the front and back positions of the mark A, and a monitoring unit 513 that monitors the front and back position deviation of the mark A based on the front and back positions of the mark A adjusted by the position adjustment unit 511. It is.

  As a result, it is possible to easily detect a sudden front / back position shift of the image while accurately reading the front / back position of the image formed on the paper P at a low cost.

  Further, according to the image reading apparatus 7 according to the present embodiment, the first scanner is based on the printing position of the mark A read by the first scanner 701a and the printing position of the mark A read by the second scanner 701b. A machine difference adjustment unit 515 that adjusts a machine difference between the first scanner 701a and the second scanner 701b is further provided. The position adjustment unit 511 adjusts the machine difference by the machine difference adjustment unit 515. The adjustment reference position of the mark A, which is a reference for monitoring the positional deviation, is determined.

  As a result, the image reading device 7 can shorten the time required to detect the front / back position deviation of the mark A as compared to the case where the front / back position deviation of the mark A is carried twice by one scanner 701. it can.

  Further, according to the image reading apparatus 7 according to the present embodiment, the machine difference adjustment unit 515 adjusts the machine difference based on the mark A formed on the same surface of the paper P.

  Thereby, the image reading apparatus 7 can accurately detect the machine difference of each scanner 701.

  Further, according to the image reading apparatus 7 according to the present embodiment, when the monitoring unit 513 monitors the front / back position deviation of the mark A formed on the paper P, the adjustment reference for the mark A determined by the position adjustment unit 511 is used. Among the positions, the first adjustment reference position of the mark A formed on the first surface P_1f of the paper P, and the print position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a The second adjustment reference position of the mark A formed on the second surface P_2f of the paper P among the adjustment reference positions of the mark A determined by the position adjustment unit 511, The second adjustment reference deviation amount with respect to the printing position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b is monitored, and the position adjustment unit 511 is monitored by the monitoring unit 513. 1 adjustment reference deviation amount, Based on a second adjusted reference shift amount monitored by the viewing unit 513, adjusts the front and back position of the mark A.

  Thereby, the image reading apparatus 7 can monitor the front / back positional deviation of the mark A at low cost.

  The image forming system 1 according to this embodiment includes the image reading device 7 described above and the image forming device 5 that forms an image on the paper P.

  As a result, as in the case of the image reading device 7, the image forming system 1 can easily detect a sudden front / back position shift of the image while accurately reading the front / back position of the image formed on the paper P at a low cost. can do.

  The image forming system 1 can provide a low-cost feedback system as a whole system.

  Further, according to the program according to the present embodiment, the image forming apparatus 5 forms the marks A on the front and back of the paper P, and the first scanner 701a for reading the marks A and the downstream side of the first scanner 701a are provided. , A second scanner 701b for reading the mark A, and a computer for controlling the image reading apparatus 7 based on the print position of the mark A read by at least one of the first scanner 701a and the second scanner 701b. The position adjustment unit 511 that adjusts the front / back position of the mark A and the monitoring unit 513 that monitors the front / back position shift of the mark A based on the front / back position of the mark A adjusted by the position adjustment unit 511.

  As a result, as in the case of the image reading device 7, the program can easily detect a sudden front / back position shift of the image while accurately reading the front / back position of the image formed on the paper P at a low cost. it can.

Embodiment 2. FIG.
In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. In the second embodiment, the machine difference of each scanner 701 is adjusted using the master document, and the front / back position deviation of the mark A on the paper P is monitored using the mark A formed on the master document as a design reference.

  FIG. 10 is a diagram illustrating an example of the conveyance path 700 of the paper P according to the second embodiment of the present invention. As shown in FIG. 10, a first scanner 701 a and a second scanner 701 b are provided along the conveyance path 700. Therefore, in the transport path 700 of FIG. 10, the first surface P_1f of the paper P can be read by the first scanner 701a, and the second surface P_2f of the paper P can be read by the second scanner 701b.

  In the conveyance path 700 of FIG. 10, the master document is used as the paper P when the machine difference between the scanners 701 is adjusted. In the master document, the printing position of the mark A formed on the first surface P_1f and the printing position of the mark A formed on the second surface P_2f are respectively formed in the same position in the front and back through direction of the paper P. It is.

  In the conveyance path 700 of FIG. 10, the machine difference adjustment unit 515 reads the print position of the mark A formed on the first surface P_1f of the master document read by the first scanner 701a and the second scanner 701b. The machine difference of each scanner 701 is adjusted based on the printing position of the mark A formed on the second surface P_2f of the master document.

  In the conveyance path 700 of FIG. 10, the position adjustment unit 511 uses the master document as the machine difference adjustment unit 515 and adjusts the machine difference of each scanner 701 as the adjustment reference position of the mark A to the master document. The printing position of the formed mark A is set as the design reference position of the mark A.

  In the transport path 700 of FIG. 10, the monitoring unit 513 is formed on the first surface P_1f of the paper P read by the first scanner 701a when monitoring the front / back position deviation of the mark A formed on the paper P. The first design reference position between the print position of the mark A and the first design reference position of the mark A formed on the first surface P_1f of the master document among the design reference positions of the mark A set by the position adjustment unit 511. Monitor the amount of deviation.

  10, the monitoring unit 513 is formed on the second surface P_2f of the paper P read by the second scanner 701b when monitoring the front / back position deviation of the mark A formed on the paper P. The second design reference position between the printing position of the mark A and the second design reference position of the mark A formed on the second surface P_2f of the master document among the design reference positions of the mark A set by the position adjusting unit 511 Monitor the amount of deviation.

  Further, in the conveyance path 700 of FIG. 10, the position adjustment unit 511 performs the mark A based on the first design reference deviation amount monitored by the monitoring unit 513 and the second design reference deviation amount monitored by the monitoring unit 513. Adjust the front and back position.

  Next, a control example of the control unit 51 in the transport path 700 of FIG. 10 will be described. FIG. 10 is a diagram illustrating an example of the conveyance path 700 of the paper P according to the second embodiment of the present invention.

  In step S41, the first scanner 701a reads the mark A formed on the first surface P_1f of the master document. In step S42, the second scanner 701b reads the mark A formed on the second surface P_2f of the master document. In step S43, the machine difference between the first scanner 701a and the second scanner 701b is adjusted.

  As mentioned above, the process of step S41-S43 is a machine difference adjustment process.

  In step S44, the mark A formed on the master document is set as the design reference position.

  Note that the process of step S44 is a process of determining a design reference position that is performed when the front / back position deviation of the paper P is monitored.

  In step S45, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S46, it is determined whether or not there is a deviation between the mark A formed on the first surface P_1f of the paper P and the first design reference position of the first surface P_1f of the design reference positions. If it is determined that there is a deviation between the mark A formed on the first surface P_1f of the paper P and the first design reference position of the first surface P_1f of the design reference positions, the process proceeds to step S47, and in step S47. The shift of the first surface P_1f is adjusted, and the process proceeds to step S48. On the other hand, when it is determined that there is no deviation between the mark A formed on the first surface P_1f of the paper P and the first design reference position of the first surface P_1f of the design reference positions, the process proceeds to step S48.

  In step S48, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S49, it is determined whether or not there is a deviation between the mark A formed on the second surface P_2f of the paper P and the second design reference position of the second surface P_2f of the design reference positions. If it is determined that there is a difference between the mark A formed on the second surface P_2f of the paper P and the second design reference position of the second surface P_2f of the design reference positions, the process proceeds to step S50, and in step S50 The deviation of the second surface P_2f is adjusted, and the process proceeds to step S51. On the other hand, if it is determined that there is no deviation between the mark A formed on the second surface P_2f of the paper P and the second design reference position of the second surface P_2f of the design reference positions, the process proceeds to step S51.

  In step S51, it is determined whether or not the monitoring is ended. If it is determined that the monitoring is to be terminated, the process is terminated. On the other hand, if it is determined that the monitoring is not ended, the process returns to step S45.

  As described above, the processes in steps S45 to S51 are the monitoring process and the position adjustment process.

  Next, machine difference adjustment and front / back position deviation adjustment will be specifically described. FIG. 12 is a diagram illustrating an example of front / back position adjustment of the mark A according to the second embodiment of the present invention. The zeroth sheet in FIG. 12 corresponds to a master document for machine difference adjustment performed before monitoring, and the first and subsequent sheets correspond to a monitoring sheet P performed after machine difference adjustment.

  Specifically, for the 0th sheet, machine difference adjustment of each scanner 701 is performed before monitoring the front / back position deviation of the mark A formed on the master document. For example, the printing position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted in accordance with the printing position of the mark A on the second surface P_2f of the master document. Further, before the first sheet for monitoring is read by each scanner 701, processing for setting a design reference position for use in monitoring is performed.

  In the first and subsequent sheets, the front / back position deviation of the mark A is monitored based on the design reference position set before the first sheet. For example, on the nth sheet, the printing position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted in accordance with the second design reference position set before the first sheet.

  The design reference position for monitoring is set to the printing position of the mark A formed on the master document, but is not limited to this. For example, when the machine difference adjustment is performed on the 0th sheet, the adjustment is made in accordance with the master document. Therefore, the design reference position for monitoring may be the print position of the mark A that has been adjusted on the 0th sheet. .

  In the above description, an example in which a master document is used has been described. However, the master document is not limited to a master document as long as there is no deviation as in the master document. That is, it may be a document T from which the positional relationship can be read from the front and back with the same reference.

  Specifically, the document T may have a round hole or a square hole penetrating from the front surface to the back surface of the document T. In this case, it is possible to read the same hole position from the front surface and the back surface of the document T. Alternatively, the document T may be a document T that has front and back position marks with special ink that penetrates from the front surface to the back surface of the document T or from the back surface to the surface of the document T. Alternatively, the original T may be a member that penetrates from the front side to the back side of the original T and does not interfere with sheet passing, such as a stapler needle.

  As described above, in the image reading apparatus 7, the machine difference of each scanner 701 is adjusted based on the mark A formed on the master document, and the mark A formed on the master document is set as the design reference position of the mark A.

  Accordingly, the machine difference of each scanner 701 is adjusted based on the absolute reference, and the front / back position deviation of the mark A formed on the paper P is monitored based on the absolute reference. Therefore, the machine difference of each scanner 701 and the front / back of the mark A are detected. The position can be adjusted with high accuracy.

  Further, in the image reading apparatus 7, the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a and the design standard of the mark A formed on the first surface P_1f of the master document. The first design reference deviation amount from the position is monitored, and the print position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b and the second surface P_2f of the master document are formed. The second design reference deviation amount from the design reference position of the mark A is monitored, and the front and back positions of the mark A are adjusted based on the first design reference deviation amount and the second design reference deviation amount.

  Therefore, since the front / back position of the mark A is adjusted based on the absolute front / back position deviation of the mark A, the front / back position deviation of the mark A can be accurately monitored.

  From the above description, according to the image reading apparatus 7 according to the present embodiment, when the machine difference is adjusted, the master original is used as the paper P, and the mark A formed on the first surface P_1f of the master original is printed. Each of the position and the printing position of the mark A formed on the second surface P_2f of the master document is formed at the same position in the front and back penetration direction of the paper P, and the machine difference adjustment unit 515 The printing position of the mark A formed on the first surface P_1f of the master document read by the scanner 701a and the printing position of the mark A formed on the second surface P_2f of the master document read by the second scanner 701b. Based on this, the machine difference is adjusted, and when the machine difference is adjusted by the machine difference adjustment unit 515 using the master document, the position adjustment unit 511 forms the mark A on the master document as the adjustment reference position. The printing position of the indicia A is set to the design reference position of the mark A, those.

  As a result, the image reading apparatus 7 can accurately adjust the machine difference between the scanners 701 and the front and back positions of the mark A.

  Further, according to the image reading apparatus 7 according to the present embodiment, when the monitoring unit 513 monitors the front / back position deviation of the mark A formed on the paper P, the first reading of the paper P read by the first scanner 701a is performed. The printing position of the mark A formed on the surface P_1f and the first design reference position of the mark A formed on the first surface P_1f of the master document among the design reference positions of the mark A set by the position adjustment unit 511. The first design reference deviation amount is monitored, and the print position of the mark A formed on the second surface P_2f of the paper P read by the second scanner 701b and the design reference of the mark A set by the position adjustment unit 511 Among the positions, the second design reference deviation amount from the second design reference position of the mark A formed on the second surface P_2f of the master document is monitored, and the position adjustment unit 511 monitors the first design monitored by the monitoring unit 513. No standards Based on the amount, a second design criterion deviation amount is monitored by the monitoring unit 513, adjusts the front and back position of the mark A, those.

  As a result, the image reading apparatus 7 can accurately monitor the front / back position deviation of the mark A.

Embodiment 3. FIG.
In the third embodiment, the same components as those in the first and second embodiments are denoted by the same reference numerals, and the description thereof is omitted. In the third embodiment, the second scanner 701b monitors the front / back position deviation of the mark A based on the front / back position of the mark A adjusted by the first scanner 701a.

  FIG. 13 is a diagram illustrating an example in which different paper P is transported in the paper P transport path 700 according to the third embodiment of the present invention. In the conveyance path 700 of FIG. 13, a reverse path 751b is provided on the upstream side of the first scanner 701a. The reversing path 751b in FIG. 13 faces down the face-up paper P transported from the upstream side and transports it to the first scanner 701a on the downstream side. Therefore, if the paper P passes through the reverse path 751b, the first scanner 701a can read the second surface P_2f of the paper P, and the second scanner 701b can read the first surface P_1f of the paper P. If the paper P does not pass through the reverse path 751b, the first scanner 701a can read the first surface P_1f of the paper P, and the second scanner 701b can read the second surface P_2f of the paper P.

  In the transport path 700 of FIG. 13, the position adjusting unit 511 has a print position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a and the paper P read by the first scanner 701a. The front and back positions of the mark A are adjusted based on the printing position of the mark A formed on the second surface P_2f. In the conveyance path 700 of FIG. 13, when the position adjustment unit 511 adjusts the front and back positions of the mark A, the position adjustment unit 511 determines the adjustment reference position of the mark A that serves as a reference for monitoring the displacement of the front and back positions of the mark A by the monitoring unit 513. To do.

  13, the second scanner 701b reads the mark A formed on the paper P when the monitoring unit 513 monitors the front / back position deviation of the mark A. Further, in the transport path 700 of FIG. 13, the monitoring unit 513 monitors the adjustment reference position of the mark A determined by the position adjustment unit 511 and the second position when monitoring the front / back position deviation of the mark A formed on the paper P. The adjustment reference position deviation amount from the printing position of the mark A read by the scanner 701b is monitored.

  In the conveyance path 700 of FIG. 13, the position adjustment unit 511 adjusts the front and back positions of the mark A based on the adjustment reference deviation amount monitored by the monitoring unit 513.

  Next, a control example of the control unit 51 in the transport path 700 of FIG. 13 will be described. FIG. 14 is a flowchart for explaining a control example in the third embodiment of the present invention.

  In step S71, the first scanner 701a reads the mark A formed on the first surface P_1f of the paper P. In step S72, the first scanner 701a reads the mark A formed on the second surface P_2f of the paper P. In step S73, it is determined whether the front and back positions of the mark A have been adjusted. If it is determined that the front and back positions of the mark A have been adjusted, the process proceeds to step S75. In step S75, the print position of the mark A formed on the first surface P_1f of the paper P and the second surface P_2f of the paper P are formed. The adjustment reference position is determined based on the printed position of the mark A. On the other hand, if it is determined that the front and back positions of the mark A are not adjusted, the print position of the mark A formed on the first surface P_1f of the paper P and the second surface P_2f of the paper P are formed in step S74. Based on the printing position of the mark A, the front and back positions of the mark A are adjusted, and the process returns to step S71.

  The processing in steps S71 to S75 is processing for determining the adjustment reference position that is performed when the front / back position deviation of the paper P is monitored.

  In step S76, the second scanner 701b reads the mark A formed on the first surface P_1f of the paper P. In step S77, it is determined whether or not there is a deviation between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f among the adjustment reference positions. If it is determined that there is a deviation between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f among the adjustment reference positions, the process proceeds to step S78, and in step S78. The shift of the first surface P_1f is adjusted, and the process proceeds to step S79. On the other hand, when it is determined that there is no deviation between the mark A formed on the first surface P_1f of the paper P and the first adjustment reference position of the first surface P_1f among the adjustment reference positions, the process proceeds to step S79.

  In step S79, the second scanner 701b reads the mark A formed on the second surface P_2f of the paper P. In step S80, it is determined whether or not there is a deviation between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f among the adjustment reference positions. If it is determined that there is a difference between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f among the adjustment reference positions, the process proceeds to step S81, and in step S81 The deviation of the second surface P_2f is adjusted, and the process proceeds to step S82. On the other hand, when it is determined that there is no deviation between the mark A formed on the second surface P_2f of the paper P and the second adjustment reference position of the second surface P_2f among the adjustment reference positions, the process proceeds to step S82.

  In step S82, it is determined whether or not the monitoring is ended. If it is determined that the monitoring is to be terminated, the process is terminated. On the other hand, when it is determined that the monitoring is not ended, the process returns to step S76.

  As described above, the processes in steps S76 to S83 are the monitoring process and the position adjustment process.

  Next, the front / back position deviation adjustment will be specifically described. FIG. 15 is a diagram illustrating an example of front / back position adjustment of the mark A according to the third embodiment of the present invention. The front and back 0th time in FIG. 15 is performed before the monitoring and corresponds to the paper P for front / back position adjustment, and only the reading result of the first scanner 701a is used. In the first and subsequent times of FIG. 15, the monitoring paper P performed after the front / back position adjustment corresponds, and only the reading result of the second scanner 701b is used.

  Specifically, in the 0th time of the front and back, the front and back position adjustment is performed by the first scanner 701a performed before monitoring the front and back position deviation of the mark A formed on the paper P. For example, the printing position of the mark A on the second surface P_2f read by the first scanner 701a is adjusted in accordance with the printing position of the mark A on the first surface P_1f read by the first scanner 701a.

  In the first front and back, processing for determining an adjustment reference position for use in monitoring is performed. In the second and subsequent times, the front / back position deviation of the mark A is monitored based on the adjustment reference position determined in the first time. For example, on the nth sheet, the printing position of the mark A on the second surface P_2f read by the second scanner 701b is adjusted in accordance with the second adjustment reference position determined on the first sheet.

  Even if the printing position of the mark A matches the design value, when the adjustment reference position is determined for the first sheet, the adjustment is performed so that there is no difference from the adjustment reference position determined for the first sheet.

  In the case of the reversing path 751b provided in the transport path 700 of FIG. 13, the front and back positions are adjusted with different paper P, but the present invention is not limited to this. FIG. 16 is a diagram illustrating an example in which the same paper P is transported in the paper P transport path 700 according to the third embodiment of the present invention.

  In the conveyance path 700 of FIG. 16, a reverse path 751a is provided between the first scanner 701a and the second scanner 701b. Therefore, the first scanner 701a can read the paper P conveyed face up. Further, the reversing path 751a can face down and transport the paper P conveyed face-up to the downstream side. Accordingly, the inversion path 751a in FIG. 16 allows the first scanner 701a to read the first surface P_1f of the paper P for the first time and to read the second surface P_2f of the paper P for the second time. Accordingly, the reversing path 751a in FIG. 9 can cause each scanner 701 to read different surfaces of the same sheet P, that is, the first surface P_1f and the second surface P_2f.

  As described above, in the image reading device 7, the first scanner 701 a causes the printing position of the mark A formed on the first surface P — 1 f of the paper P and the printing position of the mark A formed on the second surface P — 2 f of the paper P. Based on this, the front and back positions of the mark A are adjusted.

  Further, in the image reading apparatus 7, when the front and back positions of the mark A are adjusted by the first scanner 701a, the adjustment reference position of the mark A that is a reference for the front and back position deviation of the mark A is determined.

  Accordingly, since the front / back position deviation of the mark A is monitored based on the reading result of the first scanner 701a, it is not necessary to adjust the machine difference of each scanner 701. Therefore, it is possible to monitor the front / back position deviation of the mark A without being affected by the machine difference of each scanner 701.

  In the image reading apparatus 7, the second scanner 701b monitors the front / back position deviation amount of the mark A, and the front / back position deviation of the mark A is adjusted based on the monitoring result.

  Therefore, even if there is a machine difference between the second scanner 701b and the first scanner 701a, the second scanner 701b is relative to the adjustment reference position of the mark A determined based on the reading result of the first scanner 701a. Since it is sufficient to detect such a difference, it is possible to monitor the front-and-back position deviation of the mark A particularly remarkably without being affected by the machine difference of each scanner 701.

  From the above description, according to the image reading apparatus 7 according to the present embodiment, the position adjustment unit 511 includes the printing position of the mark A formed on the first surface P_1f of the paper P read by the first scanner 701a, and When the front / back position of the mark A is adjusted based on the print position of the mark A formed on the second surface P_2f of the paper P read by the first scanner 701a, the monitoring unit 513 monitors the front / back position deviation of the mark A. The adjustment reference position of the mark A serving as the reference is determined.

  Thereby, the front / back position deviation of the mark A can be monitored without being affected by the machine difference of each scanner 701.

  Further, according to the image reading device 7, the second scanner 701 b reads the mark A formed on the paper P when the monitoring unit 513 monitors the front / back position deviation of the mark A, and the monitoring unit 513 When monitoring the front / back position deviation of the mark A formed on the mark A, the adjustment reference deviation amount between the adjustment reference position of the mark A determined by the position adjustment unit 511 and the print position of the mark A read by the second scanner 701b. The position adjustment unit 511 adjusts the front and back positions of the mark A based on the adjustment reference deviation amount monitored by the monitoring unit 513.

  Thereby, the front-and-back position deviation of the mark A can be monitored particularly remarkably without being affected by the machine difference of each scanner 701.

  As described above, the image forming apparatus 5 and the image reading apparatus 7 according to the present invention have been described based on the embodiments. However, the present invention is not limited to this embodiment, and changes are made without departing from the spirit of the present invention. May be.

  For example, in the present embodiment, an example of an arrangement configuration in which the sheet P is in the direction in which the sheet P is horizontally conveyed and the colorimeter 703 and the calibration unit 705 are provided above and below the sheet P has been described. It is not limited. For example, it may be a configuration in which the sheet P is conveyed vertically, and the colorimeter 703 and the calibration unit 705 are provided on the left and right sides of the sheet P.

  In addition, an example in which the image reading signal Sout is determined by the RGB color system as digital image data (RGB code) including R color, G color, and B color components has been described. However, the present invention is not limited to this, and L * a * It may be determined by a different color system such as b * color system.

DESCRIPTION OF SYMBOLS 1 Image forming system 3 Paper feeding apparatus 5 Image forming apparatus 7 Image reading apparatus 8 Paper discharge apparatus 9 Paper discharge tray 11 Image forming apparatus main body 12 Image reading part 121 1st platen glass 122 2nd platen glass 123 Light sources 124-126 Mirror 127 Image forming optical unit 128 Image sensor 14 Automatic document feeder 141 Document placing unit 142a, 142b, 143, 144 Roller 145 Reversing unit 146 Discharge tray 20 Paper feed unit 200 Paper feed cassette 201 Feeding roller 30 Transport unit 300 Transport Path 302A Paper feed roller 302B, 302C, 302D Transport roller 303 Registration roller 304 Paper discharge roller 305 Paper discharge tray 306 Branching section 307A Circulating paper path 307B Reverse conveyance path 307C Refeeding conveyance path 41 Control section 43 Image processing section 51 Control unit 511 Position adjustment unit 513 Monitoring unit 515 Machine difference adjustment unit 60 Image forming unit 601, 601Y, 601M, 601C, 601K Image forming unit 611, 611Y, 611M, 611C, 611K LED writing unit 612, 612Y, 612M, 612C, 612K development unit 613, 613Y, 613M, 613C, 613K photosensitive drum 614, 614Y, 614M, 614C, 614K charging unit 616, 616Y, 616M, 616C, 616K cleaning unit 620 intermediate transfer unit 621 intermediate transfer belt 622, 622Y, 622M, 622C, 622K Primary transfer roller 623 Secondary transfer roller 624 Belt cleaning device 630 Fixing unit 631 Heating roller 632 Pressure roller 633 Heating unit 81 Positioning detection 83 temperature detection unit 700 transport path 701 scanner 701a first scanner 701b second scanner 703 colorimeter 705,705a~705c calibration unit 731 transport rollers 751,751a, 751b reversing path P Paper

The present invention relates to an image forming system .

The present invention has been made in order to solve the conventional problems, and an object of the present invention is to suddenly read out the front and back positions of an image formed on a sheet while accurately reading the front and back positions of the image at low cost. An object of the present invention is to provide an image forming system capable of easily detecting a shift.

In order to achieve the above object, an image forming system according to the present invention includes an image forming unit that forms an image on a sheet, a sheet on which an image is formed by the image forming unit is directly conveyed, and a reading that reads the conveyed image The image forming unit forms a mark used for adjusting the printing position on the sheet, and the reading unit reads the mark formed on the sheet and during continuous image formation over a plurality of sheets. A monitoring unit for monitoring a deviation amount between a reference position of the mark formed on the sheet and a printing position of the mark formed on the sheet read by the reading unit ; and continuous image formation based on the deviation amount And an adjusting unit that adjusts the printing position with respect to the succeeding paper .

In the image forming system according to the present invention, the image forming unit forms a mark on the first surface and the second surface of the paper to be printed on both sides, and the reading unit is formed on the first surface of the paper. The monitoring unit reads the mark and the mark formed on the second surface, and the monitoring unit shifts the reference position and the printing position of the mark formed on the first surface of the paper read by the reading unit. The first reference deviation amount is monitored, and the second reference deviation amount, which is the deviation amount between the reference position and the printing position of the mark formed on the second surface of the sheet read by the reading unit, is monitored. Preferably, the adjustment unit adjusts a print position in double-sided printing based on the first reference deviation amount and the second reference deviation amount.

The image forming system according to the present invention includes an image forming unit that forms an image on a sheet, and a reading unit that directly conveys the sheet on which the image has been formed by the image forming unit and reads the conveyed image. The image forming unit forms marks on the first surface and the second surface of the paper to be printed on both sides, and the reading unit is formed on the marks formed on the first surface of the paper and the second surface. The first reference position of the mark formed on the first surface of the paper and the first surface of the paper read by the reading unit are formed during continuous image formation over a plurality of paper sheets. The first deviation amount from the printed position of the marked mark is monitored, and the second reference position of the mark formed on the second surface of the paper and the second surface of the paper read by the reading unit are formed. A monitoring unit for monitoring a second deviation amount from the printing position of the mark; And the amount is, on the basis of the second shift amount, and a adjuster for adjusting a print position for subsequent sheet in the continuous image formation is intended.

The image forming system according to the present invention further includes an image forming unit that forms an image on a sheet, and a first scanner and a second scanner that read an image formed on the sheet, and the image forming unit includes double-sided printing. A mark is formed on the first surface and the second surface of the sheet to be printed, the first scanner reads the mark formed on the first surface of the sheet, and the second scanner is formed on the second surface of the sheet. During the formation of a continuous image over a plurality of sheets by reading the formed mark, the first reference position of the mark formed on the first surface of the sheet and the first of the sheet read by the first scanner The first deviation amount from the printing position of the mark formed on the surface is monitored, the second reference position of the mark formed on the second surface of the sheet, and the second position of the sheet read by the second scanner. Second with the printing position of the mark formed on the surface A monitoring unit that monitors the amount of misalignment, and an adjustment unit that adjusts the print position with respect to subsequent sheets in continuous image formation based on the first shift amount and the second shift amount. It is.

Further, in the image forming system according to the present invention, the determination for determining the first reference position of the mark formed on the first surface of the sheet and the second reference position of the mark formed on the second surface of the sheet. It is preferable to provide a part .

  Further, in the image forming system according to the present invention, the determination unit determines the first reference position by reading a mark formed on the first surface of the sheet by the first scanner, and determines the first reference position by the second scanner. It is preferable that the second reference position is determined by reading a mark formed on the second surface of the sheet.

In the image forming system according to the present invention, it is preferable that the determination unit determines the first reference position and the second reference position based on a design reference .

  Further, in the image forming system according to the present invention, the determining unit reads the mark formed on the first surface of the first sheet of the image forming continuous over a plurality of sheets by the first scanner. The first reference position is determined, and the second reference position is determined by reading, with the second scanner, a mark formed on the second surface of the first sheet of image forming continuous over a plurality of sheets. Preferably, the monitoring unit monitors the first shift amount and the second shift amount in the second and subsequent sheets of image formation continuous over a plurality of sheets.

Further, in the image forming system according to the present invention, the second scanner is downstream in the transport direction with respect to the first scanner, and opposite to the first scanner with a transport path through which paper is passed. It is preferable to be provided .

  In the image forming system according to the present invention, it is preferable that four marks are formed corresponding to the corners of the sheet.

Claims (17)

A first scanner for reading an image formed on a sheet;
A second scanner that is provided on the downstream side of the first scanner and on the opposite side of the first scanner across a conveyance path for passing the paper, and reads an image formed on the paper;
An image reading apparatus comprising:
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or The printing position of the mark formed on the first surface of the document that is read by the first scanner and that can read the positional relationship from the front and back on the same basis, and the second surface of the document that is read by the second scanner A machine difference adjusting unit that adjusts a machine difference between the first scanner and the second scanner based on a printing position of the formed mark;
When the machine difference is adjusted by the machine difference adjustment unit, a first reference position that is a reference position of a mark formed on the first surface of the paper and a reference of the mark formed on the second surface of the paper A position adjusting unit that determines a second reference position that is a position;
A first reference deviation amount, which is a deviation amount between the first reference position determined by the position adjustment unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. And a second reference deviation amount that is a deviation amount between the second reference position determined by the position adjustment unit and the printing position of the mark formed on the second surface of the sheet read by the second scanner. A monitoring unit for monitoring
Comprising
Image reading device. The position adjusting unit is
Furthermore, for adjusting the print position when a mark is formed on a sheet based on the first reference deviation amount monitored by the monitoring unit and the second reference deviation amount monitored by the monitoring unit. Providing feedback to the image forming apparatus;
The image reading apparatus according to claim 1. The machine difference adjusting unit is
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, Adjusting the machine difference between the first scanner and the second scanner;
The image reading apparatus according to claim 1. A reversing path for reversing the sheet between the first scanner and the second scanner or upstream of the first scanner;
When the machine difference is adjusted by the machine difference adjustment unit, the first scanner reads an image formed on a sheet that is not reversed by the reversing path, and the second scanner is reversed by the reversing path. Read the image formed on the
The image reading apparatus according to claim 3. The machine difference adjusting unit is
Adjusting the machine difference based on a mark formed on the first surface of the same sheet read by the first scanner and the second scanner;
The image reading apparatus according to claim 3 or 4. The machine difference adjusting unit is
Adjusting the machine difference based on a mark formed on the first surface of different sheets read by the first scanner and the second scanner;
The image reading apparatus according to claim 3 or 4. The machine difference adjusting unit is
A printing position of a mark formed on the first surface of the document read by the first scanner and a printing position of a mark formed on the second surface of the document read by the second scanner. Based on the difference between the first scanner and the second scanner,
The image reading apparatus according to claim 1. The position adjusting unit is
When the machine difference is adjusted by the machine difference adjustment unit, the first reference position and the second reference position are determined based on a printing position of a mark formed on the document.
The image reading apparatus according to claim 7. An image forming unit that forms images on the front and back of the paper,
A first scanner for reading an image formed on a sheet;
A second scanner that is provided on the downstream side of the first scanner and on the opposite side of the first scanner across a conveyance path for passing the paper, and reads an image formed on the paper;
An image forming system comprising:
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or The printing position of the mark formed on the first surface of the document that is read by the first scanner and that can read the positional relationship from the front and back on the same basis, and the second surface of the document that is read by the second scanner A machine difference adjusting unit that adjusts a machine difference between the first scanner and the second scanner based on a printing position of the formed mark;
When the machine difference is adjusted by the machine difference adjustment unit, a first reference position that is a reference position of a mark formed on the first surface of the paper and a reference of the mark formed on the second surface of the paper A position adjusting unit that determines a second reference position that is a position;
A first reference deviation amount, which is a deviation amount between the first reference position determined by the position adjustment unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. And a second reference deviation amount that is a deviation amount between the second reference position determined by the position adjustment unit and the printing position of the mark formed on the second surface of the sheet read by the second scanner. A monitoring unit for monitoring
Comprising
Image forming system. The position adjusting unit is
Feedback for adjusting a printing position when a mark is formed on a sheet based on the first reference deviation amount monitored by the monitoring unit and the second reference deviation amount monitored by the monitoring unit. To the image forming unit,
The image forming system according to claim 9. The machine difference adjusting unit is
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, Adjusting the machine difference between the first scanner and the second scanner;
The image forming system according to claim 9 or 10. A reversing path for reversing the sheet between the first scanner and the second scanner or upstream of the first scanner;
When the machine difference is adjusted by the machine difference adjustment unit, the first scanner reads an image formed on a sheet that is not reversed by the reversing path, and the second scanner is reversed by the reversing path. Read the image formed on the
The image forming system according to claim 11. The machine difference adjusting unit is
Adjusting the machine difference based on a mark formed on the first surface of the same sheet read by the first scanner and the second scanner;
The image forming system according to claim 11 or 12. The machine difference adjusting unit is
Adjusting the machine difference based on a mark formed on the first surface of different sheets read by the first scanner and the second scanner;
The image forming system according to claim 11 or 12. The machine difference adjusting unit is
A printing position of a mark formed on the first surface of the document read by the first scanner and a printing position of a mark formed on the second surface of the document read by the second scanner. Based on the difference between the first scanner and the second scanner,
The image forming system according to claim 9 or 10. The position adjusting unit is
When the machine difference is adjusted by the machine difference adjustment unit, the first reference position and the second reference position are determined based on a printing position of a mark formed on the document.
The image forming system according to claim 15. A first scanner for reading an image formed on a sheet;
A second scanner that is provided on the downstream side of the first scanner and on the opposite side of the first scanner across a conveyance path for passing the paper, and reads an image formed on the paper;
A computer for controlling an image reading apparatus comprising:
Based on the printing position of the mark formed on the first surface of the paper read by the first scanner and the printing position of the mark formed on the first surface of the paper read by the second scanner, or The printing position of the mark formed on the first surface of the document that is read by the first scanner and that can read the positional relationship from the front and back on the same basis, and the second surface of the document that is read by the second scanner A machine difference adjusting unit that adjusts a machine difference between the first scanner and the second scanner based on a printing position of the formed mark;
When the machine difference is adjusted by the machine difference adjustment unit, a first reference position that is a reference position of a mark formed on the first surface of the paper and a reference of the mark formed on the second surface of the paper A position adjusting unit that determines a second reference position that is a position;
A first reference deviation amount, which is a deviation amount between the first reference position determined by the position adjustment unit and the printing position of the mark formed on the first surface of the paper read by the first scanner, is monitored. And a second reference deviation amount that is a deviation amount between the second reference position determined by the position adjustment unit and the printing position of the mark formed on the second surface of the sheet read by the second scanner. A monitoring unit for monitoring
Program to function as.

Images